The former Florida governor will address the Democratic National Convention this week as a supporter of President Barack Obama after having endorsed him on the eve of the Republican convention in his home state. Crist is expected to defend Obama as a leader who has delivered for Florida — starting with the Recovery Act, which Crist endorsed — and rebuke his former compatriots in the GOP as ideologically extreme.

For the Obama campaign, Crist is an unquestionably helpful surrogate, especially in the pivotal swing state he once governed. Though he lost a 2010 Senate race after bolting the GOP, Crist’s popularity back home remains relatively strong. With Obama seeking to woo independents, women and seniors by branding Republicans as a radical party, Crist can only help bolster that message.

In Florida, Crist’s speech looks as much like a launch event for his political comeback as it does an earnest plea for middle-of-the-road voters to support Obama. The next gubernatorial election is only two years away, when unpopular Republican Gov. Rick Scott must seek another term. Associates say that Crist hasn’t made up his mind about whether to enter the race, but there’s a distinct possibility that he could compete for his old job — this time as a Democrat.

Even if Crist is undecided about a gubernatorial run, his speech in Charlotte — his exact slot hasn’t been announced — will mark the start of a campaign for renewed political relevance. While Democrats are delighted to have Crist on their side in the presidential race, there’s considerably more ambivalence among his fellow Floridians about whether they want him as their statewide standard-bearer. And there’s real reluctance to talk about the onetime self-described “pro-gun, pro-life, anti-tax Republican” as anything but a booster for the president.

Democratic National Committee Chairwoman Debbie Wasserman Schultz said Crist will talk in his speech about how Obama “made decisions that were hard but right” in order to save the U.S. economy. But she declined to go any further in speculating about Crist’s future: “I’m focused on the next 64 days and reelecting President Obama and Debbie Wasserman Schultz, … I’m not worried about the gubernatorial election in 2014.”

She wasn’t the only Florida Democrat to take that line.

“If you’re asking me was I surprised that Gov. Crist came out against the Republicans’ ticket? No. If you’re asking me have I engaged it any further than that? No,” said Florida Democratic Party Chairman Rod Smith. “I’m not surprised a lot of Republicans and independents would come out against this Republican ticket.”

As for putting up Crist for governor, Smith quipped: “I was raised a Baptist, and if you want to leave your church and join our congregation, that’s fine with us. That doesn’t mean we necessarily make you minister.”

Former Florida Chief Financial Officer Alex Sink, the party’s 2010 nominee for governor, said Crist could help Obama win over “independent-minded voters, and Charlie Crist has decided the Republican Party’s become too extreme for him.”

“If he were to run for office, there’d be a lot of explaining to do,” said Sink, who hasn’t ruled out another run for governor herself. “Once we get past November, [the governor’s race] is a 24-month process. By the time we get to a Democratic primary, there will have been plenty of time to vet all the candidates and listen to their message.”

It’s far from clear what Crist’s message to a Democratic primary electorate would be or even if he has a clear sales pitch to deliver. Crist’s record in office includes Democratic-friendly priorities like expanding voting rights and protecting the Everglades, but it also features stances on taxes, abortion, national health care and more that clash with the party’s liberal base.

There was an obvious point of rupture for Crist with the Republican Party: his support for the federal stimulus, which spelled doom in a Senate primary against Marco Rubio. But before he exited the GOP, Crist frantically tried to run to Rubio’s right, calling himself the “true conservative” in the race and attacking Rubio’s past support for some restrictions on guns.

Yet the weakness of the Florida Democratic bench could also make Crist the party’s best shot at knocking off a governor they loathe with an incredible passion. There are a handful of Democrats who might test their luck in the governor’s race — including Sink and Smith as well as Orlando Mayor Buddy Dyer and several state senators — but no one who could clear the primary field.

What’s more, Crist’s final year in office included a high-profile veto of an education reform bill teachers’ unions opposed, earning him the sincere affection of an important Democratic interest group. After leaving office, Crist set up shop at the law firm Morgan & Morgan, which is headed by one of the state’s top litigators and Democratic fundraisers. He has no shortage of Democratic friends.

In effect, Crist could take the Mitt Romney path to a new party’s nomination: triumphing over a divided set of opponents not as the candidate Democrats love but as the candidate they need to win.

Former Democratic state Sen. Dan Gelber, who served in the Legislature during Crist’s term as governor, urged his party to “embrace” Crist as one of their own in 2012. Gelber said Democrats should keep an open mind about the future, though he cautioned he’s “not promoting [Crist] to run for governor, by any means.”

“As governor, he was a basically nonpartisan guy. He vetoed a very harsh ultrasound bill. He was very good on the Everglades,” said Gelber. “I think most thoughtful Democrats are going to realize that we’ve lost too many state government elections in Florida over the last decade, and we’re not going to win them in the future by stiff-arming people who feel ill at ease in the Republican Party.”

John Morgan, the powerhouse trial lawyer who hired Crist, said the governor’s race isn’t yet on his friend’s radar. The presidential race, on the other hand, was a natural entry point into the national fray for Crist, who grew to respect Obama through their work on the stimulus and the BP oil disaster.

“I don’t think he agrees with everything this president has done. He’s more of a conservative, I think. But when he looks at both of [the presidential candidates], it’s a no-brainer,” Morgan said. “I think he’s just flabbergasted that overnight, Jeb Bush is saying things like Ronald Reagan couldn’t be nominated in our party anymore.”

Asked if Crist might have trouble winning over Democratic primary voters, Morgan had a rapid-fire response: “No more than Rick Perry had winning over Republicans in Texas after he switched or Ronald Reagan in California.”

As Democrats untangle their complicated feelings about Crist, Republicans are treating him with deadly seriousness as a potential threat to the governor’s office. The same night Crist announced his support for Obama, the Republican Party of Florida released a heated statement calling the endorsement a “repugnant display from a self-centered career politician.”

When Crist speaks to Democrats in Charlotte, RPOF Chairman Lenny Curry will be on hand to respond to the remarks, a state party aide said. In a statement, Curry called Crist an “opportunist who’s spent decades espousing conservative politics that run contradictory to everything Obama says he believes.”

In addition to what they see as a brazen ideological flip-flop and betrayal on Crist’s part, Republicans fume over the rank mismanagement of the state party during Crist’s term. The governor placed a political crony, Jim Greer, in the chairman’s job. Greer has since been indicted on charges of fraud and embezzlement; he stands trial after Election Day but not too late to embarrass Crist in a race for governor.

Still, for all those obvious liabilities, Crist’s support for Obama has earned him something of a protective cocoon — at least for now — from the national Democrats who wanted him on their team in 2012.

One prominent party strategist argued that Crist is “more closely aligned with Barack Obama” on cultural and social welfare issues than he was with the GOP and went so far as to predict that Crist will have a future in the party.

“I don’t believe Democratic voters are going to be stunned by Charlie Crist being a Democrat now instead of a Republican, and I think he’s going to be able to find an ideological home there,” the strategist said.

Former Rep. Robert Wexler, a Democrat who endorsed Crist’s independent campaign for Senate, said he considered it “totally” plausible for Crist to seek the governor’s office as a Democrat.

Wexler, who spoke to Crist last week, views him as a strong validator for Obama: “I think Gov. Crist can deliver a very powerful message that says, No. 1, the president’s stimulus package was instrumental in helping Florida get through our toughest economic days.”

“I thought he was a very good Republican governor of Florida. I think he’d be a phenomenal Democratic governor of Florida,” he added.